Union Butterfield 1599(M) High-Speed Steel Straight Flute Tap, For Cast Iron, Nitride Finish, Round Shank With Square End, Bottoming Chamfer, M8-1.25 Thread Size Hand threading tap with straight flutes cuts threads in through holes and blind holes Nitride finish for increased hardness and wear-resistance, suitable for abrasive materials such as cast iron Produces ANSI standard right-hand threads in metric sizes High-speed steel is compatible with a variety of materials Round shank with square end allows tap to be used in hand or power-driven applications